At its founding in 1343, it called Placencia Soraluze then in the fifteenth century it added "las Armas" or "weapons" to its name in reference to its main industry.

Its coat of arms consists of the following elements: a field of gules a castle battlements three gold exiting their respective sides small white flags with the cross of Burgundy.

The name "Placencia" is common, under similar forms, as seen in other foundations of earlier medieval villages like Plasencia, Piacenza or Plencia.

Soraluce (with the current Basque script is written Soraluze) appears to be the former name of the place where the town was founded.

Until the last quarter of the twentieth century, the arms industry has remained at the base of the economy of the town and today the village retains that designational fruit of its historical economic activity.